Sound record tablet



Oct. 11, 1932. c. HUENLICH SOUND RECORD TABLET Filed Jan. 4, 1930 Patented Oct. 11, 1932 UNITED STATES PATENT OFFICE CHARLES HUENLIGH, F BLOOMFIELD, NEW JERSEY, ASSIGNOR TO THOMAS A. EDISON, INCORPORATED, OF WESTORANGE, NEW JERSEY, A CORPORATION OF NEW JERSEY soonn RECORD TABLET I Application-filed January 4, 1930. Serial No. 418,447.

The present invention. relates to sound record tablets and more particularly to hollow cylindrical sound records or sound record tablets having bores of an improved construction or formation. My invention also relates to improved apparatus and an improved method for producing such record tablets.

In .order to facilitate the application and removal of a hollow cylindrical record or tablet to and from a record support, and at the same time provide ample means for frictionally maintaining the record in position on the support, it has been found desirable to taper the longitudinal bore of the record .1 and to provide some form of spaced bearing surfaces on said bore. These bearing surfaces on the bore of the record or tablet have usually been made in the form of a fiat helix generated around the longitudinal axis of the 2 record. Considerable spoilage has resulted in the past in the production of records having'such an internal construction due to the difliculty' of removal from the core around which they have been formed without distorting or otherwise injuring the records. The removal is usually accomplished by hand before the record is completely cooled, and while the wax or wax-like material of which the record is principally formed is still. in

3 a semi-plastic state. It is obvious that to remove such a record from the core it is neces sary to twirl or rotate it around the core; the number of rotations necessary to remove a given record depending, of course, on the pitch or angle given to the projections or threads of the helix provided on the bore of .the record. WVith the flat helix generally used, a correspondingly small pitch or angle is given to these projections or threads, the result being that considerable twirling and manipulation is required to remove the record from the core, which twirling greatly increases the likelihood of injury and distortion to the record while in the semi-plastic state. It has also been found upon using records having this internal construction, that when the record is being applied to or removed from a record support, the edges and the bearing surfaces of the helical projections are quite likely to become so chipped and marred as to render the record unsuitable for repeated use; it being understood that it is de sirable to have the record capable of Withstanding at least 30.0 applications to a record support.

One object of my invention is to provide an'improved apparatus for molding records which is of such construction as to enable a record to be easily and quickly removed therefrom with a very slight amount of twirling or manipulation, and with little or no danger of injury or distortion to the record.

Another object of the invention is to provide a mold having an improved core which will produce projections on the bore of a record of such formation that repeated applications of the finished record to a record support will result in little or no injury to the edges and surfaces of the projections.

Another object of the invention is to provide an improved record preferably so constructed that it cannot be easily broken, and having internal projections so formed as to enable the record to be readily removed from a molding core without injury thereto, said internal projections also preferably afiording ample bearing surface to engage a record support with sufficient friction properly to hold the record in place thereon without damage to the projections.

Still another object of the invention is to provide an improved method or process of producing records or record tablets of the improved construction described above.

Other and further objects of the invention 3 will be obvious upon an understanding of the preferred embodiment about to be vdescribed or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon [employment of the invention in practice.

A preferred embodiment has been chosen for purposes of illustration and description and is shown in the drawing accompanying and forming a part of this specification, wherein:

Figure 1 is a longitudinal cross-section of a record in accordance with my invention, m0 showing the internal projections thereof;

Fig. 2 is an elevation partly in section, of my improved molding apparatus showing a record being formed therein;

Fig. 3 is a perspective View of a portion of the record shown in Fig. 1;

Fig. 4 is a perspective view of the porous fabric liner or reenforcing member which is embedded in the record; and

Fig. 5 is a transverse cross-section on line A-A of Fig. 1.

Referring to the drawing, the numeral 1 represents the shell or casing of a cylindrical mold 2 having a uniform bore, and 3 represents a core which is longitudinally and concentrically disposed within the mold casing. The outer surface of core 3 is preferably tapered and has steep, broad rifling 4: cut therein forming thereon lands or projections 5 of the same breadth and depth as the rifiing. The angle or pitch of the rifling, as shown in the preferred embodiment, is such that a record cast about the core can be removed therefrom by turning it through aproximately a quarter of one complete turn or rotation. Variations in the amount of turning necessary to effect the removal of the record are within the spirit and scope of my invention, as the purposes of the invention will be attained if the rifling is so formed that approximately one complete rotation or less will serve to remove the record from the core of the mold. However, the most effective results are attained upon employing rifling having approximately the same angle or pitch as the rifling of the record shown and described herein as the preferred embodiment. Under these conditions the longitudinally extending edges of the helical lands or projections on the core will each be at an angle of less than 40 to the longitudinal axis of the core; likewise the edges of the helical projections produced on the inner surface of a record tablet cast in the mold. will each be at an angle of less than 40 to the axis of the tablet. V

The lower and larger end of the tapered part of core 3 has the rod 7 extending there from through openings formed in the base 8 of the mold and in an annular disc 9, which disc is rigidly attached to the shaft 7 and abuts the lower end of the core. The disc 9 is slightly smaller in diameter than the inside of the mold shell or casing 1 so that it will fit fairly closely within said shell and yet be free to slide longitudinally therein. When the core 3 is in its normal operative position in the mold, the disc 9 is disposed in the opening in. the base 8 and extends a slight distance into the casing 1 of the mold, while the rod 7 extends downwardly below the base 8.

The smaller upper end of the tapered part of core 3,when the latter is in its normal operative position in the mold, does not extend quite to the top of the latter. Above its tapered portion the core 3 has a long cylindrical extension 10 which is slightly less in diameter than the upper end of said tapered portion and is provided with a shoulder 11 at a point slightly above such tapered portion. lVhen the core 3 is in its normal position the extension 10 projects a considerable distance above the top of the mold.

In forming a record in the mold, I prefer to place a tapered reenforcing tube 14 made of a sized stiff or semirigid and porous fabric or foraminous material, over the core 3. The tube conforms closely to the lands of the core from the point slightly above the bottom of the latter to a point slightly above the top of the tapered portion thereof, but substantially below the top of the mold and a short distance below the shoulder 10. Hot, fluid wax-like material, of which the record is to be formed, is now poured into the mold 2 and percolates through the porous fabric of the tube 14 and around the core 3. This material is then allowed to cool'for a few minutes during which time it solidifies. A slight shrinkage of the wax-like material occurs while cooling, which causes it to recede slightly (as indicated in Fig. 2) below the top of the mold but not to the level of the shoulder 11 of the core extension 10. The upper end of the formed record 6 is then trimmed ofl fiush with the shoulder 11, as indicated by dotted lines in Fig. 2. The bottom disc 9, the core 3 and the record 6 are now moved upwardly together through the mold 2 by means of the rod 7 until the disc 9 is flush with the top of the mold. At this point the record is given a twirling or angular movement of approximately 90 about the core 3 and with the same motion is lifted and separated from the core. It is then placed on a rack for further cooling after which it is reamed, turned down to proper size, and finished. The extension 10 of the core serves as a guide for the record during the operation of separating the latter from the core. It will be obvious that the rifiing 4 and lands or projections 5 of the core will respectively form the lands or projections 15 and the rifiing 16 on the internal surface of they record 6, as the reinforcing fabric tube 14 placed over the core 3 is made of porous or foraminous material which permits the fluid wax-like material to percolate freely through it and into close engagement with the core 3. The tube 14, of course, becomes embedded in the record 6 closely adjacent the bottom of the rifling l6 and serves to greatly strengthen the record and to prevent the record from being easily cracked or broken.

From the foregoing it will be seen that when a record made in the manner just described is placed on a reeordsupport such as a mandrel having a plurality of longitudinally extending record engaging members, the latter will engage and extend across the projections or lands 15 at quite an acute angle with the edges thereof. Accordingly any material chipping, marring or breaking down of the edges and surfaces of such projections or lands in the application of the record to such a support and in the removal thereof from the support, will be prevented.

It will also be seen that the actual extent of the surface of the projections or lands 15 of record 6 which will be in bearing engagement with the said longitudinal members of such a mandrel, will be substantially as great as with a record having the old form of internal projections. Thus I have produced a record which is simple to manufacture and of such construction that there is little or no danger of damaging the same by removal thereof from the mold core, and

the likelihood of chipping, marring or grooves formed thereon.

It is to be understood that various changes may be made in the above'described apparatus, product and method without departing from the spirit of the invention, and that all matter herein is to be interpreted as illustrative, and not in a limiting sense.

Having thus described my invention, I claim:

1. A hollow cylindrical record tablet having rifling on its internal surface, said rifling being so formed as to make less than one complete turn while progressing substantially the entire length of the tablet.

2. A hollow cylindrical phonograph record tablet having rifling formed on its in-' ternal surface, said rifling being so formed that when the record tablet is placed on a core having similar and cooperating rifling, the tablet will be moved longitudinally through a distance substantially equal to its length by rotating the same on said core through an angle of less than 360.

5. A hollow cylindrical record tablet having a projection on its internal surface extending substantially the length of the tablet, said projection being so formed that the longitudinally extending edges of said projection are at angles of less than 40 to the longitudinal axis of the tablet.

4. A hollow cylindrical record tablet having a semi-rigid porous re-enforcing fabric embedded therein and longitudinally extending projections formed on its internal surface, said projections being soformed that their longitudinally extending edges are at angles of less than 40 to the longitudinal axis of the tablet. V

5. A hollow cylindrical phonograph record tablet having stifi, porous, re-enforcing fabric embedded therein, and longitudinally extending projections on its inner surface, said projections being of such a form that the longitudinal edges thereof are each at an angle of less than 40 to the longitudinal axis of the tablet.

This specification signed this 31st day of December, 1929.

CHARLES HUENLIGH. 

